Bring water and coconut milk to a boil in a medium saucepan. Whisk in peanut butter, curry powder and half of the seasoning packet (discard the remainder or reserve for another use). Add noodles and peas and carrots; cook until the noodles are tender and the vegetables are heated through, about 3 minutes. Stir in shrimp and heat through. Divide the soup between 2 bowls and top with cilantro and a squeeze of lime juice.